1. Technical Field
The present invention relates to a robot hand for holding and transporting an article, a robot and a robot system provided with a robot hand, and a method for controlling a robot hand.
2. Description of the Related Art
In the field of industrial robots, there is known a robot provided with a robot hand including a linearly reciprocable holding part for holding an article such as a workpiece (see e.g. Japanese Laid-open Patent Publication No. 2002-172569 and Japanese Laid-open Patent Publication No. 2006-16144).
A conventional robot hand, which includes a linearly reciprocable holding part, is mounted on a wrist disposed at the distal end of a robot arm at a base of the robot hand functioning as a supporting point. When the robot hand holds an article placed at a position away from the wrist, the robot hand moves the holding part toward the article, and then holds and lifts the article by the holding part which is disposed at a position away from the base.
At this time, a load moment depending on the distance between the holding part for holding the article and the base, and on the weight of the article is applied on the base and the wrist. In a robot hand including a linearly reciprocable holding part, it is necessary to reduce the load moment applied on the base and the wrist when the holding part disposed at a position away from the base lifts the article.
Further, in the configuration in which a robot hand including a linearly reciprocable holding part is attached to a robot arm, the load inertia is applied on the robot arm when transporting the article held by the holding part by the operation of the robot arm. It is also necessary to reduce the load inertia applied on the robot arm.